Maybe it will happen to you that the pen draws broken lines, like in the pictures below. You may think there is an issue with the pen. However if your Pen Display has Touch Bar or Dual Touch Bar function and the Touch Bar is automatically working by itself, the broken lines are probably caused by not working well Touch Bar.
We would suggest that you can test drawing in diagnostic tool in the driver. By the way, please kindly take a video that can show the problem clearly in diagnostic tool with full screen. Contact us through service@huion.com to send us the video. Once we confirm, we will provide you with a new version of firmware to forbid Touch Bar function so that you could use the pen normally. If your pen display has been out of warranty and you do not want to spend much money to buy a new one, disabling Touch Bar or Dual Touch Bar function can be a good way to make your pen display working fine.